﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Runtime.InteropServices;

namespace test_interface{
    public class DllInvoke
    {
        #region Win API
        [DllImport("kernel32.dll")]
        private extern static IntPtr LoadLibrary(string path);

        [DllImport("kernel32.dll")]
        private extern static IntPtr GetProcAddress(IntPtr lib, string funcName);

        [DllImport("kernel32.dll")]
        private extern static bool FreeLibrary(IntPtr lib);
        #endregion

        private IntPtr hLib;        
        public DllInvoke(String DLLPath)
        {
            hLib = LoadLibrary(DLLPath);
        }

        ~DllInvoke()
        {
            FreeLibrary(hLib);            
        }

        //将要执行的函数转换为委托
        public Delegate Invoke (string APIName,Type t)  
        {
            IntPtr api = GetProcAddress(hLib, APIName);
            return (Delegate)Marshal.GetDelegateForFunctionPointer(api, t);
        }
    }
    
}
